The sign you normally call yours — the one you get from your birthday — is your Sun sign, and the date alone decides it. Your Rising Sign (Ascendant) is a different thing: it is the sign that was climbing over the eastern horizon at the exact minute, and in the exact place, you were born. Two people born on the same day can have completely different Rising Signs.
That one is your sun sign. It is fixed by where the Sun sat on the ecliptic on the day you were born, and the Sun moves only about one degree a day. The date alone settles it.
A rising sign (Ascendant) is measured from the ground, not the sky — it is the point of the ecliptic that was just crossing the eastern horizon at your moment, at your place. The Earth turns once a day, so that point travels through all twelve signs in a single day. What the sun sign does in a year, the rising sign does before breakfast tomorrow.
Same day (15 May 1990), same city (Seoul). We changed only the time.
| Birth time | Rising sign | Position within the sign |
|---|---|---|
| 06:00 | Gemini | 3.4° |
| 08:00 | Cancer | 3.5° |
| 10:00 | Cancer | 28.9° |
| 12:00 | Leo | 23.1° |
| 14:00 | Virgo | 17.5° |
| 18:00 | Scorpio | 6.4° |
| 22:00 | Sagittarius | 25.9° |
How we measured — we entered 1990-05-15, latitude 37.5665, longitude 126.9780, UTC+9 into the calculator on this page and changed only the hour. These are not numbers we made up.
Two people born on the same day in the same city: the one born in the morning rises in Gemini, the one born at night in Sagittarius. Seven signs in one day.
Cut it finer. At 12:00 the Ascendant was Leo 23.1°. Four minutes later, 12:04, it was 23.9° (0.8° of travel). Thirty minutes later, 12:30, it was 29.2° (6.1°). Two hours later, 14:00, it had crossed into Virgo altogether. So being half an hour wrong about your birth time can move you across a sign boundary. That is why we will not calculate one without a time.
The horizon tilts differently depending on where you stand, so the same clock time at a different latitude lands on a different degree of the same sign. Holding local noon fixed and changing only the city, we measured: Seoul Leo 23.1°, New York 19.9°, London 23.4°, Sydney 8.7°. The sign held, but Sydney was 14.4 degrees away from Seoul — and of the four, Sydney is the one whose latitude differs most (−33.9°, southern hemisphere). We measured only these four, so we will not go as far as claiming "the further the latitude, the bigger the gap."
We did not invent this. The 2nd-century Greek astronomer Ptolemy called this point the horoskopos (ὑροσκόπος, "the hour-marker") in his Tetrabiblos. The English word "horoscope" comes from it. Of the four angles — eastern horizon, midheaven, western horizon, lower midheaven — this is the first.
Our job ends at doing that calculation faithfully. We show you the method the old book set down and the number it yields, and we stop there.
Then we will not calculate one, because we do not invent figures. Places worth checking: a birth certificate, a hospital record, a maternity notebook; family memory (though memory is usually off by half an hour or more); an old Korean saju reading, which if it records the hour pillar narrows you to a two-hour window.
If the time is truly lost, the sun sign is still open to you. It is fixed by date alone, so no time means no error — it is simply a different thing to look at.
⚠ This is a calculation method set down in an old book, and the number it produces. It is not a statistic and it is not a prediction. We show you how the figure is arrived at; we do not tell you who you are or how you should live. That part is yours.